It's a testament to this game's cool core concepts that I enjoyed my time despite 3 of my 4 playthroughs running into problems. It's fun to experiment, move around and kill, and there's a good variaty of powers you need to do without. Now as to those problems:
My first playthrough I stopped because heal was bound by default to a, not q, which is of course also move left. I had to alt-f4 my way out and change it.
My second playthrough I tried to rush through the tutorial, and at the last point pressed q before I took damage. Since there weren't any enemies to kill to recharge healing, I was now stuck and had to do the whole tutorial again. I think the tutorial is great, but it takes a non-insignificant amount of time and isn't skipable if you start the game from scratch. I know you can restart if you complete, and I assume if you die (I never did, permantenly anyway, thanks Hades!), but I didn't find any way to restart on command except alt-f4, which put you into the tutorial again.
My third playthrouh I ascended. Huray!
My fourth playthrough I wanted to try keeping different weapons. However, when I got to the first warrior boss cube, I tried Hermes-Dashing, which knocked him remarkably far (is he lighter than regular enemies?), over a wall, and out of the level. Now I couldn't reach him or kill him. At which point I decided it was time to fill in the rating :)
And as the last two points, a lot of walls got invisible if the camera was closed, and I don't know if it's on purpose but I couldn't tell the difference between wizard-cubes with 3-round bursts and single shots until they shot me.
Still, like I said, I'm quite impressed with the core gameplay. Most of the problems I encountered are easily patchable should you feel like a post-jam version.